BA Excel Modelling

The Students’ Union Shop is trying to work out how many cashiers it needs to employ in
order to provide an adequate service level. Customers at the shop line up in a single queue
and are called forward to pay for their purchases when a till becomes free. To help determine
the busy times of the day, the shop has recorded the number of customers arriving at the tills
in each 5-minute interval during the shop’s opening hours, from 8am until 6pm (N.B. this
is the number who actually make a purchase and does not include customers who are just
browsing). Records for a period of 5 weeks are available. All the data were collected during
term time.
The shop usually functions with just three cashiers but it has the capacity to support up to
6. An extra cashier costs $20 an hour. The shop is open for approximately 50 weeks each
year. The management has also collected data about the time it takes for cashiers to take
payment. These data come from term time and 1000 records are available. Management are
concerned that customers wishing to buy food, in particular, may be going to other outlets
within the university such as the Big Ears Sandwich Shop or the Noddy Bar. Management are
also concerned about the turnover of their sta and would like to reduce their stress and also
stop them getting bored. They would be interested to hear about any innovative operating
strategies for doing this.
You have been employed as a consultant for the Students’ Union Shop and should
 Report on their current business, pointing out any existing problems;
 Suggest improvements to their current strategies;
 Provide them with an ecient tool for easily evaluating their current performance using
the data provided or new data in a similar format.